Spark plug



B B O c H R G U L P K R A P 3 Filed Jan. 13, 1934 SMWMY,

Patented Aug. 27, 1935 UNITED STATES PATENT OFFICE This invention relates to spark lugs and has ior its principal object to provide a spark plug for internal combustion engines which is of inexpensive manufacture.

Another object of the invention is to provide a spark plug, the shell or which is, made from standard tubing o'r'pipe. Y I

A further object ofthe invention is to provide a spark plug especially for automobile engines, which is cheap to manufacture yet practical and eflicient. 5

e For a clear understanding of the invention, the same will be hereinafter fully described as illustrated in the accompanying drawing, and the novel features thereof will be particularly pointed out in the appended claims.

In the drawing, Figure l is a side elevation of a spark plug constructed in accordance with my invention,

Fig. 2 is a longitudinal section view thereof,

Fig. 3 is a bottom plan view of Fig. 1,

Fig. '4 is a similar view to Fig; 1 illustrating a modification, and

Fig. 5 is a bottom plan view of Fig. 4.

Referring to the drawing, 1 represents the. shell of a spark plug, which is preferably constructed from tubing or pipe of the standard or ordinary merchant stock. Said shell is threaded externally at 2 for fixing the spark plug into the head of the engine and is cut oil to proper length. A ring flange 3, which is also cut from pipe of standard merchant stock is internally threaded at 4 for engaging the threads 2 of the shell and serves as a shoulder and provides means for making the shell of the spark plug tight in the engine against leakage.

The lower or inner and threaded end of the shell is bored internally at 5 to provide an annular shoulder 6, against which is seated a disc of metal 1 having a central opening 8. An insulation member 9 of circular form is reduced in diameter at its upper or inner end leaving a neck ID for entering and filling the opening 8 of the disc I and providing an annular shoulder at H for engaging the lower side of the disc. The insulation member 9 is provided with a vertical or longitudinal central opening l2 for receiving the center or positive electrode l3. A circular backing plate or washer I4 is adapted to engage the lower or outer end of the insulation member 9 and is provided with an opening [5 through which the electrode [3 passes.

Enclosing the upper open end of the shell I is a cap [6 of insulating material, which cap is cut down at I! for engaging the end of the shell and leaving 'a depending circular portion for entering the inside of the shell and centering the cap thereon. The cap I6 is provided with a central opening IQ for the center electrode 13, and said electrode not only serves its usual function but is employed and serves also to bind the disc I, the member'li and the backing washer M to the cap 1'6 and hold all said parts in position relative to the shell. This is accomplished by providing the lower end of the electrode l3 with a shoulder flange 20 which is adapted to engage the backing plate l4, and a binding nut 2| on the upper threaded portion 22 of said electrode engages a washer 23 resting against the cap 15. Openings 24 of suitable size and number are provided through the side of the shell near its upper end 'for permitting the escape of the heat, and thereby serving as ventilating ancl cooling means for the full length of the spark plug.

In the modification illustrated in Figs. 4 and 5, the metal disc I is replaced by a disc 25, which is cut down at 26 thereby providing a tight seat against the lower end 21 of the shell and being centered thereon by the raised central portion 28. The backing plate 29 has an upturned peripheral flange 30, which engages the side surface of the insulation member 9 and its position relative to the'disc 25 is such that the spark occurs at 3| as will be understood.

The spark plug illustrated and described although designed primarily for cheapness of manufacture is practical and efficient. The lower insulating member 9 is protected by the backing plate M, which together with the disc 1 and said insulating member therein make the lower end of the spark plug tight against leakage due to the upward pressure thereagainst from the operation of the engine. It is obvious that the greater the pressure the greater the sealing effect at all joints or points of contact of the parts. By ventilating the interior of the spark plug the efficiency thereof is increased by preventing deterioration of the parts from warping.

Although the construction disclosed is well adapted to carry out the invention, it will be understood that changes in the details may be made within the scope of the claims.

Having fully described my invention, what I claim is:

1. A spark plug, comprising a shell, means closing the shell, the means being located at the lower end of the shell, the means having an opening therethrough, a member of insulating material, the member having a neck adapted to enter said opening of said means from the lower side thereof, and a central electrode passing through said member.

2. A spark plug, comprising a shell, a metal disc closing said shell and engaging the lower end thereof, the disc from below having an opening therethrough, a member of insulating material, the member having a reduced neck adapted to enter said opening of said disc, and a central electrode passing through said member and holding said member against said disc and retaining both in position.

3. A spark plug, comprising a shell, a metal disc closing the lower end of the shell, the metal disc having an opening therethrough, a member of insulating material, said member having a neck adapted to enter said opening, said member having a shoulder adapted to engage the lower side of said disc, a central electrode passing through said member, and said electrode retaining said member and said disc in position.

4 A spark plug, comprising a shell, a metal disc closing the lower end of the shell, the disc having an opening therethrough, a member of insulating material, the member having a neck adapted to pass through said opening, a central electrode passing through said member, means carried by said electrode for holding said member against said disc, and means for retaining said electrode in position.

5. A spark plug, comprising a shell, a metal disc closing the lower end of the shell, the disc having an opening therethrough, a member of insulating material, the member having a neck adapted to enter said opening, a central electrode passing through said member, a backing plate for said member, a flange carried by said electrode adapted to engage said backing plate, and means for causing said electrode to exert pressure against said plate.

6. A spark plug, comprising a shell, 2, metal disc closing the lower end of the shell, the disc having a central opening, a member of insulating material, said member having a neck adapted to enter the opening of said disc, a central electrode passing through said member, a cap of insulating material for the shell, said electrode extending through the cap, a flange carried by the electrode adapted to retain said member in position, and means for causing said electrode to draw said member and said cap towards each other for holding same in position.

7. A spark plug, comprising a shell, a metal disc closing the lower end of the shell, the disc having a central opening, a member of insulating material, said member having a neck adapted to enter said opening, a cap of insulating material, the cap resting against the upper end of the shell, a central electrode, the electrode passing through said member and said cap, a flange carried by said electrode beyond said member, and a nut on said electrode beyond said cap adapted to drawsaid. member and said cap toward each other for securing same in position.

8. A spark plug, comprising a shell, the lower end of the shell being bored to provide an annular shoulder, a disc, the disc engaging said shoulder, the disc having a central opening, a member of insulating material, the member having a neck adapted to enter said opening, a cap of insulating material, the cap resting against the upper. end of the shell, a central electrode,

the central electrode passing through said member and said cap, and means for causing said electrode to exert drawing pressure against said member and said cap for holding same in position.

9. A- spark plug, comprising a tube, a metal disc adapted to close one'end of the tube, the disc having a central opening, a member of insulating material, the member having a neck adapted to enter said opening, a cap of insulating material adapted to close the other end of said tube, an electrode passing through said member and said cap'in spaced relation to said tube, and means for causing said electrode to bind said member and said cap in position in said tube.

10. A spark plug, comprising a tube, a metal disc adapted to close one end of the tube, the disc having an opening, a memberof insulating material, the member having a neck adapted to enter said opening, a cap of insulating material adapted to close the other end of said tube, an

electrode passing through said member and said cap in spaced relation to said tube, means for causing said electrode to bind said member and said cap in position in said tube, and the tube being provided with means for permitting the escape of heat from the interior thereof.

' RICHARD H. COBB. 

